Which physical mechanism is responsible for magnetic properties of cuprates upon doping?

An international team of researchers has identified and proved that adding impurities with a lower concentration of electrons stabilizes the antiferromagnetic state of cuprates, high-temperature superconducting compounds based on copper. The research team, led by a senior fellow at Ural Federal University, Evgeny Stepanov, has published the results of the study in npj Quantum Materials.

"We study collective electronic effects in various materials, especially in those that are characterized by fairly strong electron-electron interaction," says Evgeny. "This interaction leads to such effects as charge ordering, magnetism, superconducting state and others. In this article, we investigated how the properties of cuprates change when impurities are added to the system to reduce the electron concentration in the material. Usually, such a process is called hole doping, and the absence of an electron is called a hole."

Cuprates - Antiferromagnets - State - Change - Properties

It is known that cuprates are antiferromagnets in the normal state. Upon doping, the change in the magnetic properties of various cuprates can occur in two scenarios: either antiferromagnetism is destroyed and goes into a canted antiferromagnetic state, or holes begin to form their own magnetic state, which is characterized by a certain wavenumber.

"In the compound that was studied, we witnessed the second scenario, in which antiferromagnetism is stabilized due to strong electron interactions. The holes form their magnetic state, which leaves the antiferromagnetic state unchanged increasing with doping," explains Evgeny Stepanov. "What is important is that this process occurs in a wide range of electron concentrations. This allows the antiferromagnetic state to be in resonance at a certain energy. It...